1. Field of the Invention
The present invention relates to integrated circuits. More particularly, the present invention relates to integrated circuits having multiple voltage power supply requirements and to a power-up and power-down circuit for use on such an integrated circuit.
2. The Prior Art
As integrated circuit functions become more complex, the power-supply requirements for the integrated circuits also increase in complexity. For example, an emerging trend is to provide both analog and digital functions on the same integrated circuit die. The power supply requirements for an integrated circuit including both analog and digital functions include provision for more than one voltage to be supplied to the integrated circuit. Typical requirements for such an integrated circuit fabricated according to presently-practiced technology may include the requirement to supply both 1.5 volts and 3.3 volts for circuitry internal to the integrated circuit.